April is “STI AWARENESS” Month

Chlamydia trachomatis, is the most common notifiable disease in the United States. It is among the most prevalent of all STDs, and since 1994, has comprised the largest proportion of all STDs reported to CDC (Table 1). Studies also demonstrate the high prevalence of chlamydial infections in the general U.S. population, particularly among young women.1

Chlamydial infections in women are usually asymptomatic.2 Untreated infection can result in pelvic inflammatory disease (PID), which is a major cause of infertility, ectopic pregnancy, and chronic pelvic pain. Data from randomized controlled trials of chlamydia screening suggested that screening programs can lead to a reduction in the incidence of PID.3,4 As with other inflammatory STDs, chlamydial infection could facilitate the transmission of HIV infection.5 In addition, pregnant women infected with chlamydia can pass the infection to their infants during delivery, potentially resulting in ophthalmia neonatorum, which can lead to blindness, and pneumonia. Because of the large burden of disease and risks associated with infection, CDC recommends annual chlamydia screening for all sexually active women younger than age 25 years and women ≥25 years at increased risk for infection (e.g., women with new or multiple sex partners).6

Chlamydia — Rates of Reported Cases by Age Group and Sex, United States, 2016

Figure 1: Chlamydia Rates

In 2016, a total of 1,598,354 chlamydial infections were reported to CDC in 50 states and the District of Columbia (Table 1). This case count corresponds to a rate of 497.3 cases per 100,000 population. During 2000–2011, the rate of reported chlamydial infection increased from 251.4 to 453.4 cases per 100,000 population (Figure 1, Table 1). During 2011–2013, the rate of reported cases decreased to 443.5 cases per 100,000 population, followed by an increase in the rate of reported cases over each of the next 3 years. During 2015–2016, the rate increased 4.7%, from 475.0 to 497.3 cases per 100,000 population (Figure 1, Table 1).

Screening for Chlamydia 8

Routine chlamydia screening is recommended for all sexually active adolescents and young women age 25 years and under. Women over age 25 with risk factors such as new or multiple sex partners, all pregnant women, and men who have sex with men, or are in high risk settings should also be screened. Chlamydia is easily detected from a swab or urine specimen and treated with antibiotics. Rescreening and treating sexual partners prevents re-infection. The National Commission on Prevention Priorities ranks chlamydia screening as a high value, but underused clinical preventive service. Chlamydia screening could reduce the incidence of pelvic inflammatory disease (PID) by up to 60%.

Quality Measures

The Healthcare Effectiveness Data and Information Set (HEDIS) contains a measure which assesses chlamydia screening coverage of sexually active young women who receive medical care through commercial or Medicaid managed care organizations.

Among sexually active women aged 16–24 years in commercial health maintenance plans, screening increased from 23.1% in 2001 to 47.4% in 2015.

Among sexually-active women aged 16–24 years covered by Medicaid, screening rates increased from 40.4% in 2001 to 58.0% in 2011, then decreased to 55.2% in 2015. 7

Although chlamydia screening has expanded over the past two decades, many women who are at risk are still not being tested—reflecting, in part, the lack of awareness among some health care providers and the limited resources available to support these screenings.